9.5 Nuclear Power Although nuclear power does not come from a fossil fuel, it is fueled by uranium, which is obtained from mining and is non-renewable. As of 2011, there were 440 nuclear power reactors in operation and 61 nuclear power plants under construction in 13 countries. Of the 158 nuclear power plants currently being planned, most are in Asian countries such as China, India, Japan, and South Korea.

9.6 The Nature of Nuclear Energy The nuclei of certain atoms are unstable and spontaneously decompose. These isotopes are radioactive. A great deal of energy is released during nuclear disintegration.

9.7 Nuclear Chain Reaction Nuclear fission occurs when neutrons impact and split the nuclei of certain other atoms. In a nuclear chain reaction, splitting nuclei release neutrons, which themselves strike more nuclei, in turn releasing even more neutrons. Controlled chain reaction- nuclear power plant Uncontrolled chain reaction- nuclear bomb

9.8 Nuclear Fission Reactors In the production of electricity, a nuclear reactor serves the same function as a fossil-fuel boiler: It produces heat, which converts water to steam, which turns a turbine, generating electricity.

9.8 Nuclear Fission Reactors Pressurized-water reactor

The Biological Effects of Ionizing Radiation Large doses of radiation are clearly lethal. Demonstrating known harmful biological effects from smaller doses is much more difficult. The more radiation a person receives, the more likely it is that there will be biological consequences. Time, distance, and shielding are the basic principles of radiation protection. Water, lead, and concrete are common materials used for shielding from gamma radiation.

Radiation Protection Protective equipment

Reactor Safety The Three Mile Island nuclear plant in Pennsylvania experienced a partial core meltdown on March 28, 1979. It began with pump and valve malfunction, but operator error compounded the problem. The containment structure prevented the release of radioactive materials from the core, but radioactive steam was vented into the atmosphere. The crippled reactor was defueled in 1990 at a cost of about $1 billion. Placed in monitored storage until its companion reactor reaches the end of its useful life.

Reactor Safety Chernobyl is a small city in Ukraine, north of Kiev. It is the site of the world’s largest nuclear accident, which occurred April 26, 1986. Experiments were being conducted on reactor. Operators violated six important safety rules. They shut off all automatic warning systems, automatic shutdown systems, and the emergency core cooling system for the reactor.

Reactor Safety In 4.5 seconds, the energy level of the reactor increased 2000 times. The cooling water converted to steam and blew the 1102-ton concrete roof from the reactor. The reactor core caught fire. It took 10 days to bring the burning reactor under control.

Reactor Safety There were 37 deaths; 500 people hospitalized (237 with acute radiation sickness); 116,000 people evacuated. 24,000 evacuees received high doses of radiation. Children or fetuses exposed to fallout are showing increased frequency of thyroid cancer because of exposure to radioactive iodine 131 released from Chernobyl.

Reactor Safety The accident at Chernobyl

Reactor Safety The Fukushima nuclear power plant was damaged on March 11, 2011 following a magnitude 9 earthquake and tsunami. Heat exchangers were damaged, power to the site was cut off, and the diesel generators designed to provide power in an emergency were flooded and stopped operating. Explosions, fires, and leaks in the cooling system released radiation into the atmosphere and sea water.